Heat the oven to 375°F. Line a rimmed baking sheet with foil and set a wire rack on top.
In a large bowl, combine the egg, breadcrumbs, and milk. Let the mixture stand for 2 minutes so the breadcrumbs can absorb the milk.
Add the ground beef, ground pork, onion, garlic, adobo sauce, smoked paprika, salt, and black pepper. Mix gently with your hands just until combined. Avoid packing the meat mixture tightly.
Shape about half the mixture into a flat rectangle on the prepared rack. Place the pepper Jack baton lengthwise down the center, leaving a border around the edges. Cover with the remaining meat mixture and pinch the seams closed so the cheese is fully enclosed.
Lay the bacon slices across the loaf, slightly overlapping them. Tuck the ends underneath the loaf to help keep the bacon in place.
Bake until the center reaches 160°F on an instant-read thermometer, about 60 to 75 minutes. Brush the barbecue sauce over the bacon during the final 15 minutes of baking.
Let the meatloaf rest on the rack for 10 minutes before slicing. This helps the melted pepper Jack stay inside each slice.